Improvement in valves for engines



Nnluoza G.M.G|THENS.

Valve for Engines.

Patented March 23, 1875,.

UNITED STATES PATENT @Erica GEORGE M. GITHENS,

or NEW YORK, N. Y.

IMPROVEMENT. IN VALVES FOR ENGINES.

Specification forming part of Letters Patent No. 16 1,025., dated March23, 1875; application filed August 29, 1874.

To all whom it may concern:

Be itknown that I, GEORGE M. GmHENs, of the city and State of New York,have invented an Improvement in Valves for Engines, of which thefollowing is a specification:

Valves for engines have been moved for the admission of steam into acylinder to act upon a piston that is connected with the valve. In suchcases the steam has usually been admitted from the steam-chest, and ithas been necessary to cushion the piston to prevent the thumping actionof the valve-moving piston against the head of its cylinder.

My invention relates to a valve-moving device that is especiallyavailable in rock-drilling and other machinery where a long steampistoncan be made use of.

I employ the steam in the cylinder to move the valve, instead of takingit from the steamchest, and the parts are constructed so that,

as the steam-piston approaches the termination of its stroke in onedirection, the packing of the piston uncovers a hole that leads to thevalve-moving cylinder, Where the steam passes to, and acts upon, apiston, moving that and the valve, and cutting oft' the steam from oneside of the main cylinder and introducing it at the other side, and thepiston, hence, is moved the other Way until it uncovers another opening,allowing steam from the cylinder to pass to the valve-moving pistonvandthrow it and the valve the other way. The parts are so arranged thatthere is no possibility of leakage from the steam-chest into thecylinder that moves the valve.

ln the drawing, Figure l is a cross-section of the cylinder, valve, andvalve-moving piston. Fig. 2 is a longitudinal section, and Fig. 3 is aplan, with the cover of the steam-chest removed.

The steam-cylinder a, piston-rod b, and piston c are of any desired sizeand construction, except that the piston is of suftcient length toeffect the object hereafter named, and it is provided with double setsof packing-rings near the ends. lhe steam is admitted to the chest e bythe pipe j', and the exhaust g passes in below the valve-seat h. Thevalve i acts in the usual way to admit steam to either port 2 or 3, topass along the ports 4 and 5 to the ends of the cylinder a, and theexhaust returns through the same channel to the cavity 6V of the valvez', and to the exhaust-port l and pipe g. The lvalve-moving piston m isin the cylinder a, that is placed below the valve-seat and between thatand the main cylinder a, and it is provided with removableheads o o, andthis piston m is connected by the stem r with the valve t, which stempasses through the exhaust, and there are ports or openings t u from thecylinder a to the cylinder a.

When the piston c is moving in the direction shown by the arrow, Fig. 2,it uncovers the port a, and the steam-pressure rushes into the cylindern and drives the piston m into the opposite position to that shown, andmoves the valvet' with it, so as to open the port 2 to the eduction-port6 and allow the steam to pass away, and at the same instant the steam isadmitted, by the valve i, to the steam-cylinder a, through the port 3,to the other side ot' its piston, and the piston cis moved the otherWay, and near the end of this movement the piston .opens the port t, andthe steam, rushing from the cylinder a into the cylinder n, moves thepiston m and valvet back to the former position, to readmit steam at theother side of the piston. The valve@ and its piston m may be on the topof the cylinder n, or at one side, and the cylinder n may stand longitudinally or transversely to the cylinder a.

I make use of a hole, 8, running from one end of the piston m to theother, and this serves as an escape for any steam that may remain in thecylinder u after the piston m has been moved, because this hole opensinto the transverse groove in the piston m, into which the stem r of thevalve enters, and this stein does not lit the groove tightly, but itacts to close that portion of the hole leading to the side that thesteam is pressing upon, because the piston is in contact with the stemat this side, while the other portion of vthe hole is open to theexhaust, so that there will be no hinder-ance to the movement of thepiston m from any steam remaining in the cylinder.

Ei'orts have been made to admit steam from the main cylinder to thevalve-moving cylinder; but the valve was between them, and theconnection from the valve to the piston was through the steam-space, andhence the valvemoving piston was exposed to pressure from the steam inthe steam-chest, and there was risk of leakage, obstructing the movementof the valve-piston. By placing the valve-moving piston below the valve,or between it and the steam-cylinder, the valve-movin g cylinder is-opento the exhaust, and pressure can never accumulate in the same.

I claim as my inventionl. The valve-moving piston and a stem passingthrough the exhaust-port, in combination with the steam-valve and themain cylinder, piston, and ports, the valve-moving piston being locatedbetween the steam-valve and the main cylinder, for the purposes andsubstantially as specied.

2. The valve-moving piston, having openings from each end to transversegroove receiving the valve-stem, in combination with' GEORGE M. GITHENS.

Witnesses GEO. T. PINCKNEY, HAROLD SERRELL.

